Gene Variation Could Spur Longer Smoking, Earlier Cancer

Researcher suggests a change in screening policies

SOURCE: Washington University School of Medicine, news release, April 14, 2015

FRIDAY, April 17, 2015 (HealthDay News) -- A gene variation associated with smoking longer and getting lung cancer at a younger age has been identified by researchers.

People usually are screened for lung cancer based on how much they smoke and their age, the researchers said. But this new study supports the idea of using genetic information to target people who might not be screened otherwise, said study first author Dr. Li-Shiun Chen, of Washington University School of Medicine in St. Louis.

The researchers analyzed more than 24 studies that included over 29,000 smokers of European ancestry. They found that people with a certain variation in a nicotine receptor gene called CHRNA5 were more likely to keep smoking for four years after those without the variation had quit.

The average age that people quit was 52 among those without the variation and 56 among those with the variation.

People with the variation in the CHRNA5 gene also inhaled deeper when they smoked and had a higher risk of being diagnosed with lung cancer four years earlier than those without the variation, the study found. The average age of diagnosis was 61 among those with the variation and 65 for those without the variation.

The findings suggest that people with the variation should undergo lung cancer screening at a younger age, said Chen.

The study was published April 14 in the Journal of the National Cancer Institute.

A previous study by Chen and her colleagues found that people with the CHRNA5 variation are more likely to respond to medications to help them stop smoking.

"The same people with this high-risk gene are more likely to respond to smoking-cessation medications, such as nicotine-replacement patches, lozenges or gum," she said in a university news release.

"Although it's clear the gene increases the chances a person will develop lung cancer at a younger age, it also is clear that the risk can be reversed with treatment," Chen concluded.